This invention relates to a hydraulic control valve device for an anti-lock braking system (ABS hereinafter) and a traction control system (TCS hereinafter). More specifically, it relates to a hydraulic control valve device which uses a wide open channel during normal braking operation and uses a throttled channel during hydraulic pressure control.
A hydraulic brake device, which prevents wheel locking by electronically controlling brake hydraulic pressure when at full braking or sudden braking, is publicly known. This type of device is well-known to create noise, vibration, harshness (NVH) such as a metal sound or vibration when the electromagnetically operated normally open valve (hydraulic control valve device hereinafter) is closed. In order to resolve NVH, there exists a method of providing an independent differential pressure switching valve at the upstream side of the hydraulic control valve device of the main hydraulic braking line.
The above-described conventional method to eliminate NVH is effective to a certain degree. Metal sound or vibration, however, could not completely be eliminated which leaves room for an improvement.